The present invention relates to a semiconductor device of a CSP (Chip Size Package) type, and particularly to a structure of a redistribution wiring layer for the semiconductor device.
FIG. 2 is a configurational view of a conventional semiconductor device described in, for example, one (Japanese Unexamined Patent Publication No. 2004-31790) of patent documents 1, 2 and 3 (Japanese Unexamined Patent Publication Nos. 2004-31790, 2004-214561 and 2003-243570), wherein FIG. 2(a) is a plan view thereof, and FIG. 2(b) is a sectional view of a portion taken along line X-X in FIG. 2(a).
The present semiconductor device is of a CSP type and includes respective circuit blocks for a power supply circuit 51, an operational amplifier 52, a comparison amplifier 53, an analog circuit of an RF transmit-receive section 54 and a digital circuit of a logic section 55 all formed in its circuit forming surface. The semiconductor device has an IC 1 in which a large number of input/output terminals 2 are arranged at its outer peripheral portion. A first insulating layer 3 is formed on the circuit forming surface of the IC 1, and a redistribution wiring layer 4 is formed on the first insulating layer 3. The redistribution wiring layer 4 is constituted of a large number of bump setting wirings 4a having one ends connected to the input/output terminals 2 via through holes 5, and shield sections 4b which respectively cover the surfaces of the power supply circuit 51 and the comparison amplifier 53.
Bumps 6 are set to the other ends of the bump setting wirings 4a. The entire surfaces of the first insulating layer 3 and the redistribution wiring layer 4 are covered with a second insulating layer 7 so as to expose the heads of the bumps 6. Incidentally, the redistribution wiring layer 4 is formed of a copper plate having a thickness of 5 μm or so, and the bumps 6 are formed of solder balls. The present semiconductor device is flip-chip packaged by bonding the bumps 6 to their corresponding wirings 9 formed on a mounting board 8 as shown in FIG. 2(b).
Since the surfaces of the power supply circuit 51 and the comparison amplifier 53 formed on the circuit forming surface of the IC 1 are covered with the shield sections 4b formed of a copper plating film in the semiconductor device, the power supply circuit 51 and the comparison amplifier 53 can be protected from externally-incoming noise, thereby making it possible to improve the stability of the operation of semiconductor device.
A semiconductor device having a configuration in which in order to further enhance a shield effect and improve high-frequency characteristics, a shield section 4b is formed over substantially the entire surface of a circuit forming surface of an IC 1 except for portions for forming input/output terminals 2 and portions for forming bump setting wirings 4a, and the shield section 4b is connected to power supply terminals, has also been described in the patent document 1.